These companies are fly by night hence why they don't buy their own properties...

If you can get hold of a reliable and honest builder, you will be fine (that does not mean you will not go over budget).Low CapEx, Little Hassle, Quality Tenant, You can manage new construction out of state for the first 5-years, Tenant May Stay longer (because is a brand new house) are few benefits of new construction.You may not be able to get close to the 1% rule though.Goodluck

They tend to stay to themselves, not a lot of company or complaints. 

Specifically, is the rental market stable, and is reliable assistance (like agents, property managers, contractors, etc.) available?

You'll want a title company/closing attorney who understands how to do this correctly.

Questions Regarding Property Registration Restrictions in a Joint Venture Model:Are there any restrictions when attempting to change the property registration with the county (through the title company) if the property has an active Hard Money Loan or DSCR Loan?

For perspective, last April I closed on a new construction loan (build to rent) with a turnkey company there (Rent to Retirement).

Another avenue would be to call your utility companies and ask about installing additional meters.

These companies will end up holding on to buildings for longer than they planned, keeping inventory low. 

I collaborate with large custodian companies.